Telephone-switch-controlling system



A. E. LUNDELL.

TELEPHONE SWITCH coNTRoLLlNG SYSTEM.

APPLICATION FILED APR. I2. I9I7.

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TELEPHONE SWITCH CONTROLLING SYSTEM.

A. E. LUNDELL.

TELEPHONE swlTcH coNmoLLmG SYSTEM.

APPLICATION FILED APR. I2, 19|]- 1 ,333,027. Patented Mar. 9,1920.

A. E. LUNDELL. TELEPHONE SWITCH CONTROLLING SYSTEM.

APPLICATION FILED APR. 12. 1911.

1,333,027, Patented Mar. 9,1920.

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A. E. LUNDILL.

TELEPHONE SWITCH CONTROLLING svsEM. APPLICATION FILED APR. I2. I9|7.

1,333,027. I Patentedmr. 9,1920.

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Coun/'ng Re/s g' I /n Ven/0r FYI; Amway/7de# UNITED STATES PATENT OFFICE.

ALBEN E. LUNDELL, OF NEW YORK, N. Y., ASSIGNOIR. TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-SWITCI-I-CONTROLLING SYSTEM.

Application led April 12, 1917.

To 1U whom t may concern:

Be it known that I, ALBEN E. LUNDELL, a citizen of the United States, residing at New York, in the county of Bronx and State of New York, have invented certain new and useful Improvements in Telephone- Switch-Controlling Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to switch controlling systems, and particularly to systems for controlling the selective operation of switching devices employed in automatic or semi-automatic telephone exchanges.

The object of the present invention is to provide a simple and eiicient switching means for controlling the change-over from one selective operation to the next, or, in other wo` 1ds, for successively associating a plurality of selectively operable switching devices with a controlling circuit.

In automatic or semi-automatic telephone systemsf; there are provided a plurality7 of selectively operable switching devices, such as selector switches or devices for registering the impulses representing' the various digits of line numbers (register-senders and number indicators), that are successively associated with an impulse sending or receiving circuit through which their setting is controlled.

Heretofore this change-over operation for successively connecting the various switching devices to the controlling circuit was effected by a separate switching device, such as a sequence or side switch, controlled in turn by a relay or a plurality of relays. To avoid the necessity of providing such separate switching devices, in accordance with the present invention, a single electromagnetic switching device, preferably a relay, is provided for controlling the change-over operation. Depending on the energized or denergized condition of the mentioned relay, one selectively operable switching device after the other is operatively associated with the controlling circuit, the operation of the relay being jointly controlled by the various selectively operable switching;V

devices and the sender that is adjustable to determine the setting of said devices.

Yhile the invention is disclosed in con- Specfcation of Letters Patent.

Serial No. 161,453.

nection with a signaling arrangement between an A and a B operator of a semi-automatlc telephone system, it will be obvious to those skilled in the art that it is applicable to arrangements and systems of widely varying character without departing from the spirit of the invention. The invention may be employed, for instance, in automatic or semi-automatic telephone systems for controlling the adjustment and' operation of register-senders.

The drawings represent a semi-automatic telephone exchange system embodying the present invention. In Figure 1 a calling line circuit, a connecting operators cord circuit and a selector switch adapted to extend the same are shown; Fig. 2 represents a B operators position and associated apparatus and a party line circuit; Figs. 3 and 4f represent the called number indicating apparatus at the B operators position, and the distributing switch by means of which this apparatus may be` associated with the selected trunk; and Fig. 5 represents the connecting operators controlling device by means of which the selector switch and the other selectively operable switching devices may be adjusted. The drawings should be arranged by placing Fig. 5 below Fig. l, Fig. 2 to the right of Fig. 1, Fig. 3 to the right of Fig. 2, and Fig. 4 to the right of Fig. 3. Only so much is shown of the circuits and controlling apparatus as is necessary for a clear understanding of the present invention. The selector and sequence switches and the controlling apparatus for such switches are only schematically indicated, as their detailed larrangement has no bearing on the present invention. Devices of this type are well-known in the art and a description of the'same may be found in Patent No. 1,168,319 of January 18, 1916.

A clear understanding of the invention may be had from the following detailed description and the appended claims.

A calling subscriber at substation 100 desiring to obtain a connection with one of the parties of a line No. 731 (Fig. 2), re-

Patented Mar. 9, 1920. i

moves his receiver from the switchhook,

' into an answering jack 102 in which the calling subscribers line terminates. A circuit is established thereupon from grounded battery, through the windin of a cut-0H relay CO, the sleeve contacts oi: jack 102 and plug 101, and the windingI of relay 103, to ground. Relay CO opens the circuit of relay LR, which in turn extinguishes lamp CL. Relay 103 closes a circuit from ground through its armature and front contact, a contact 104 and the power magnet of a sequence switch 105, to grounded battery, and this sequence switch moves under the control o'f its normal spring 106 into position 2. t

When sequence switch 105 reaches position 2, a circuit is closed from ground through a sequence switch contact 107, conductor 108, a contact 500 and the power magnet of a sequence Switch 501 to grounded battery for moving this sequence switch into position 2. A circuit is now closed from grounded battery, through the winding of a magnet 502, a sequence switch contact 503 and the lefthand back contact and armature of a relay 504 to ground. Under the control of mag# net 502, wipers 505 to 509 of a cord finder switch are moved over a contact bank 1n an upward direction. When the wipers reach contacts 510 to 514. individual to a cord or trunk 109, which was taken in use by the operator in extending the call, ai circuit 1s closed from ground through a sequence switch contact 110, conductor 111, contact 511, wiper 506, a contact 515 of sequence switch 501 and the winding of relay 504 to grounded battery. Relay 504 opens'at its left-hand back contact the circuit of magnet 502, whereupon the finder is arrested with its wi ers on the contacts representing trunk 109. Ilelay 5.04 closes a circuitfrom ground, through its left-hand armature and front contact, a contact 516 and the power magnet of. sequence switch 501 to grounded battery for driving this switch out o'f position 2 into position 3. When the sequence swltch moves out of position 2 and opens contact 515 lrelay 504 does not become denergized, a locking circuit being closed from grounded battery, through the winding of this relay, sequence switch Contact 517, the rlght-hand front contact and armature of relay 504, wiper 507, contact 512, conductor 112 and sequence switch contact 113 to ground.

The connecting operator depresses now a listening key 114, connecting thus her telephone set 115 through the trunk 109, 1n telephonic association with the calling substation 100.

In accordance with the instructions received from the calling subscriber, the operator sets up on her keyboard (Fig. 5) thel number ofthe called subscriber. Supposing that the called subscribers number is 7 31-W, and that the called line terminates in an office to which lead a plurality of trunk lines terminating in the tenth group of contacts of a district selector 116, the operator depresses key 518 in the district, key 519 in the hundreds, key 520 in the tens, key 521 in the units and key 522 in the stations row of keys. These keys control a double series vof counting relays (zero to nine) 0perable in sequence by the action of a stepplng relay 523. It is' noted that the hundreds, tens and units keys are wired in the same manner as shown in connection with the station and district rows of keys. The operator then depresses a start key 524, clos- "ing a circuit from ground, through the contact of this key, a contact v525 and the power magnet of sequence switch 501, whereupon this sequence switch moves out of position.

the allotter sequence switch is moved out v otposition 1 into position 6. In this position of the allotter, another finder such as 529 is set in readiness for operation, due to the closure of a circuit from ground, through contact 530, a contact 531 and the power magnet of sequence switch 501 associated with the finder 529 to grounded battery. This sequence switch was standing -in position 18 and will now be moved into p0- sition 1.

Sequence switch 105 being in position 2, a fundamental circuit is established from grounded battery, through the winding of a relay 117, a sequence switch contact 118, a conductor 119, Contact 513, wiper 508, a sequence switch contact 533, a conductor 534, the outer armature Aand back contact of the upper zero counting relay, conductor 535, the winding of the stepping relay 523, wiper 509, contact 514, a conductor 120, and a sequence switch contact 121 to ground. Relay 117 becomes energized and closes a circuit from ground, through its right-hand armature and front contact, a sequence switch Contact 122, a conductor 123, and the power magnet of sequence switch 105 to grounded battery, for drivin@V this sequence switch into position 3, in wrhich position relay 117 remains energized, due to the closure of a locking circuit throughits lefthand front Contact and arn'iature, and a sequence switch Contact 124.

Stepping relay 523 also becomes energized and closes a circuit from ground, through its front contact and armature, a sequence switch contact 536, a conductor 537, the contact of key 518, conductor 538, the ar1nature and back contact of the upper counting relay 9 and the winding of the lower counts ing relay 9 to grounded battery. The lower counting relay 9 becomes energized and closes a circuit from ground, through a sequence switch Contact 539,?gonductor 540, the armature and front conta'c't of the lower counting relay 9, the windings of the upper and lower counting relays 9 to grounded battery. The upper counting relay 9, however, is short-circuited, due to the closure of a shunt from its winding through conductor 538, key 518, conductor 537, -sequence switch contact 536 and the front Contact of the stepping relay 523 to ground.

In position 3 of the sequence switch 105, a circuit is closed from grounded battery, through the winding of a driving magnet 125, sequence switch contact 126, and the right-hand front contact and armature of relay 117 to ground. The magnet 125 by attracting its armature 127, forces a brush rod 128 against a roller 129, constantly rotating in the direction indicated by the arrow. Under the control of this roller, the brush rod 128, with wipers 130, 131 and 132, and a commutator brush 133 mounted thereon is moved in an upward direction. Wipers 130, 131 and 132 are adapted to wipe over the contacts of terminal bank 134, and brush 133 is adapted to travel over the conducting and insulating segments 135 and 136 of a commutator plate 137.

Then brush 133 reaches the first conducting plate 135 it connects ground through a conductor 138, sequence switch contacts 139 and 124 to relay 117, causing thus the shortcircuiting of stepping relay 523. Upon its denergization, relay 523 removes the short circuit from around the winding of upper counting relay 9, and this relay becomes energized. The upper counting relay 9 connects conductor 538 through its armature and front contact and the armature and back contact of the upper counting relay 8 to the lower counting relay 8, which then operates in the same manner as the lower counting relay 9, to close a circuit for the upper counting relay 8, when brush 133 reaches the first insulated segment 136, whereupon the short circuit is removed from the winding of the stepping relay 523, and this relay permits the operation of the lower countin relay 8. The operation of the counting re ays continues in the same manner as described in connection with counting relays 9 and 8, unt-il the upper zero counting relay becomes energized. This relay opens at its outer armature and front contact, the fundamental circuit, preventing thus the renergization of'stepping relay 523. The circuit of relay 117 is opened when brush 133 encounters the next insulating segment.

Relay 117 closes a circuit from ground, through its right-hand armature and back contact, a sequence switch contact 140, conductor 123, and the power magnet of sequence switch 105 to grounded battery, for moving .this sequence switch into position 6. A circuit is now closed from grounded battery through the winding of a test relay 140 and a sequence switch contact 141 to ground. The test relay becomes energized and assuming that the first trunk in the tenth group is busy and a ground is connected to test terminal 142 of such trunk, relay 140 remains locked up due to the extension of this ground through test wiper 132, a conductor 143, and the right-hand armature, front contact and the winding of relay 140 to grounded battery. The sequence switch 105 is now in position 7, it being driven there by a circuit closed through the left-hand armature and front contact of relay 140 and a sequence switch Contact 144. Relay 140 closes a circuit from ground, through its left-hand armature and front contact, a sequence swltc-h contact 145, and the winding of the driving magnet 125 to grounded battery, and this magnet will cause the further travel of the wipers.

lVlien the wiper 132 engages test terminal 146, connected in multlple with the test terminals of trunk 147, 148 in all other district selectors, and does not find a ground connected to this terminal, relay 140 becomes denergized, and opens at its lefthand armature and front contact, the circuit of magnet 125, causing thus the stopping of selector switch 116. By releasing its righthand armature, relay 140 connects a ground potential through a sequence switch contact 149, its right-hand back contact and armature, conductor 143, wiper 132, terminal 146, and conductor 150 to the multiples of terminal 146. The seizure of trunk 147, 148 b other district selectors is thus prevente A circuit is also closed from ground through the left-hand armature and back contact of relay 140', a contact 151, and the power magnet of sequence switch 105 to grounded battery, for driving the sequence switch out of position 7 into position 11.

Upon the energization of the upper zero counting relay, a circuit is closed from ground, through a sequence switch contact 541, the inner armature and front contact of the upper zero counting relay, and the power magnet of sequence switch 501 to grounded battery, for moving the sequence switch into position 6. When the sequence switch 501.1 eaves position 4, a locking circuit of the counting relays is opened at sequence switch contact 539, and these relays become denergized.

When sequence switch 501 reaches position 6, a new fundamental circuit is established from ground (Fig. 2), through a sequence switch contact 200, trunk conductor 148, wiper 131, a sequence switch contact 152, conductor 120, contact 514, wiper 509,

the windings of stepping relay 523, conductor 535,the outer contact and armature of the upper zero counting relay, conductor 534,

sequence switch contact 533, wiper 508, contact 513, conductor 119, 'a sequence switch contact 153, wiper 130, conductor 147, a se quence switch contact 201, and the wmding of a relay 202 to grounded battery. Relay 202 closes a circuit from ground through its right-hand armatureand front contact, a sequence switch contact 203, conductor 204, and the power magnet of sequence switch 205 to grounded battery, for driving this sequence switch out of position 1 1nto posltion 2. A circuit is now closed from ground, through sequence switch contact 206, conductor 207, a Contact 300 and the power magnet of a sequence switch 301 to grounded battery, #for moving this sequence switch out of position 1 into posltion 2.

A circuit is established from grounded battery, through the right-hand armature and back contact of a relay 302, a sequence switch contact 303 and the winding of a magnet 30-1.- to grounded battery. Under the control of magnet 304, wipers 305, 306, 307, 308, 3097 310 and 310 of a trunk finder switch are moved in an upward direction over a terminal bank containing contacts representing trunks. When these wipers reach a set of contacts 311, 312, 313, 314,

315, 316 and 318' individual to trunk 147, 148 seized by district selector 116, 'a circuit is established from ground through a sequence switch contact 208, conductor 209, contact 311, wiper 305, a sequence switch Contact 317, and the winding of relay 302 to grounded battery. Upon energization relay 302 opens at its right-hand back contact the circuit of magnet 314, causing thus the arresting of the trunk linder switch. This relay closes a circuit from ground through its right-hand armature and front contact, a contact 318 and the power magnet of sequence switch 301 to grounded battery, for driving this sequence switch out of position 2 into position 6. Relay 302 is main-v tained energized, due to the closure of a locking circuit from grounded battery through its winding, a sequence switch contact 319, the left-hand front contact and armature of relay 302, wiper 306, contact 312, conductor 320, and a sequence switch contact 208 to ground.

A circuit is now closed from ground, through a sequence switch contact 321, wiper 308, contact 314, a conductcr 322, a contact 209, and the power magnet of sequence switch 205 to grounded battery, for driving this sequence switch into position 3. A circuit is closed from ground, through the right-hand armature and front contact of relay 202, a sequence switch contact 210, a conductor 211, contact 316, wiper 310, a sequence switch contact 323, a conductor 324, Vcontact 400 of a relay 401, a conductor 402, the lower conta-cts of stations, units and tens indicator springs 450, 451 and 452, respectively, and the power magnet of the hundreds indicator 403 to grounded battery. The hundreds indicator is set -in motion.

Upon the energization of the stepping relay 523, a circuit is established from ground, through the front Contact and armature of this relay, a sequence switch contact 542, a conductor 543, the hundreds key 519, a conductor 544, the armature and back contact of the upper counting relay 7, and the winding of the lower counting relay 7 to grounded battery. In the same manner as above described, the lower counting relay 7 becomes energized and prepares` a circuit for the upper counting relay 7. i

The number indicators 403, 404, 405 and 406 are of the well-known sequence switch type, and control the contacts shown in Fig. 4 between the dotted lines to the right and left of the indicators, respectively. While these indicators are moving between the positions indicated at their respective normal springs 407, 408, 409, 410 they close contacts 411, 412, 413 and 414, respectively. Thus a ground will be intermittently con- 'nected through Contact 411, conductor 419, a

sequence switch contact 325, wiper 309, contact 315, conductor 326, a sequence switch contact 212, and the left-hand armature and front contact of relay 202 to the fundamental circuit in the same manner as through commutator brush 133. The stepping magnet 523 is shunted as man times as contact 411 is closed for controlllng the successive operation of the counting relays.

When the upper zero counting relay is energized, the indicator 403 is in position 7. The opening ofthe fundamental circuit by the upper zero counting relay results in the denergization of relays 523 and 202, and the movement of sequence switch 501 into position 8. Relay 202 opens at its righthand armature and front contact the drivingcircuit of the hundreds indicator 403.

he indicator403 being -in an off-normal position and the relay 202 being denergized, a circuit is closed from grounded battery through thewinding of relay 401, hundreds indicator contact 453, the upper contact of stations indicator spring 420, a conduetor 454, sequence switch contact 323', trunk finder wiper 310', terminal 316', a conductor 326', sequence switch contact 210', and the right-hand back contact and armature of relay 202 to ground. The relay 401 becomes energized and closes a locking circuit for itself from grounded battery, through its winding and upper front contact, a conductor 455, contacts 459, A456 and 457 of the tens, units and stations indicators, respectively, conductor 458, and a sequence switch contact 345', to ground. Upon energization, relay 401 opened its contact 400 andtherefore when the fundamental circuit is again closed and the relay 202 becomes energized, instead of the indicator 403, the indicator 404 is operated. The drivingcircuit of indicator 404 extends from grounded battery, through the power magnet of this indicator, the lower contact of tens indicator spring 460, the lower contact of hundreds indicator spring 461, the lower front contact ot' relay 401, conductor 454 and then through the path traced for indicator 403 to ground at the right-hand armature of relay 202. The indicator 404 operates in the same manner as indicator 403, with the difference that it will be stepped into a position determined by key 520.

As soon as the indicator 404 moves out of position N, the locking circuit of relay 401 is interrupted in contact 459. Upon the deenergization of relay 401, the above traced driving' circuit for indicator 404 is opened, but when the indicator reaches position O, into whiclrposition it is moved under the control of the normal contact 408, a new driving circuit is closed from grounded battery, through its pow'er magnet, the upper contact of spring 452, the lower contacts of the units and stations indicatorsprings 451 and 450, respectively, and then through the path traced for the power magnet of indi- Acator 403 to ground at the right-hand armature of relay 202.

After the setting of indicator 404, the sequence switch 501 is moved into position 10 and the relay 202 connects ground to. the winding of relay 401. The relay 401 becomes energized and locks up in the above described manner. Upon the renergization of relay 202, the ground applied through the front contact of this relay to conductor 454 is extended through the lower front contact of relay 401, the lower contact of hundreds indicator spring 461, the upper contact of tens indicator spring 460, the lower contact of units indicator spring 465, and the power magnet of indicator 405 to groundedy battery.` Under the control of the units key 521, the units indicator operates in substantially the same manner as the tens indicator. Then it moves out of its normal position and opens the. contact 456, the relay 401 becomes denergized and closes through contact 400, conductor 402-, the lower contact of stations indicator spring 450, and the upper contact of units indicator spring 451, a new driving circuit for the units indicator.

Upon the setting of the units indicator, the sequence switch 501 is moved into position 12 and' the relay 202 becomes denergized and closes the above traced circ-uit for relay 401. The relay 401 locks up and when the relay 202 is again energized upon the reclosure of the fundamental circuit, ground is connected through conductor 454, the lower front contact of relay 401, the lower contact of hundreds indicator spring 461, the upper contacts of tens and units indicator springs 460 and 465, respectively, and the power magnet of the stations indicator 406, i

to grounded battery. The stations indicator is set in mot-ion and when it opens its contact 457, the locking circuit of relay 401 is opened and a new driving circuit closed through relay contact 400 and the upper contact of stations indicator spring 450.

After the impulses predetermined by key 522 have been received under the control of contact 414, sequence switch 501 moves into position 16, and the fundamental circuit is opened at the back contact of the upper zero countmg relay. Due to the fact that the upper contact of the stations indicator spring 457 is open, the relay 401 does not become energized upon the denergization of relay 202. In position 16 of the sequence switch 501, a circuit is closed from ground, through a sequence switch contact 545, wiper 505, contact 510, vconductor 546, and a contact 154 and 'the power magnet of sequence switch 105 to grounded battery, `for moving this sequence switch out of position 11 into position 16. When contact 113V is opened, relay 504 becomes denergized, and closes a circuit from ground through the left-hand armature and back contact., a contact 547, and the power magnet of sequence switch 501 to grounded battery, for moving the se- .quence switch into position 17. A circuit is then closed from ground, through a sequence switch contact 548, and the winding of a magnet 549 to grounded battery. Under the control of magnet 549, the wipers 505 to 509 of the cord finder switch are, driven in a downward direction, and when they reach the normal position, contact 550 of the nder switch is closed and a circuit is established from ground through contact 550, a contact 551 and the power magnet of sequence switch 501 to grounded'battery, for moving this sequence switch into position 18. The sequence switch will remain in this position until allotter 526 is moved into position 1, and closes a circuit vthrough its contact 528 and a sequence switch Contact 552, for driving the sequence switch out ot position 18 into position 1, and allotting thus the cord finder for service.

As soon as the indicator switch 406 reaches position O, the lower contact of spring 420 is closed, and upon the last denergization of relay 202, a circuit is established from ground, through the armature and back contact of this relay, sequence switch. contact switch 301, to grounded battery, for inoving this sequence switch out of position 6 into position 7. A circuit is then closed from ground, through sequence switch contact 329, wiper 307, contact 313, conductor 330, a contact 213 and the power magnet of sequence switch 205, to grounded battery, for moving this sequence switch out of position 3 into position 7. When sequence switch 205 reaches position 4, a circuit is closed from grounded battery, through the winding of a relay 214, the .primary winding ot a repeating coil 215, a sequence switch contact 216, trunk conductor 147, wiper 130, a sequenceswitch contact 160, the contacts of a re-ringing key .161 and the secondary winding of a repeating coil 162 to ground. Relay 214 becomes energized, and connects grounded battery through a resistance 217, its right-hand armature and contact 218 and the .winding of a relay 219 to lground for energizing relay 219. u

While sequence switch 205 ils traveling from position 4 to 5, a relay 220 is energized by a circuit extending from grounded battery, through a sequence switch c ontact 221 and the left-hand winding of this relay to ground. When sequence switch 205 leaves position 5, a holding circuit is established for relay 220 from ground, through the right-hand winding, armature and front contact of this relay and sequence switch contacts 222 and 223 to grounded battery.l

In position 7 of sequence switch 301, a circuit is closed from ground, through a sequence switch contact 334, a conductor l335 and lamps 415, 416, 417 and 418 in multiple to grounded battery. When sequence switch 4205 reaches position 7, a circuit is closed from ground through a sequence switch contact 229 and a lamp 230 to grounded battery. The lighting of lainp 230 indicates to the B operator that she may complete the connection and lamps 415 to 418 indicate that line No. 731, party W, is wanted. The

`operator inserts a plug 224 into a jack 225,

i'n which the line No. 731 terminates. A circuit is established from grounded battery, through the winding of relay 226, the sleeve contacts of plug 224 and jack 225 and a resistance 227 .to gro-und.

Relay 226 closes a circuit from ground, through its armature and front contact, the left-hand armature and front contact relay 220, a contact 228 and the power magnet of sequence switch 205 to grounded battery,

`whereupon this sequence switch is moved out of position 7 into position 9. When moving out of position 7, contact 208 is opened, whereupon relay, 302 becomes deenergized and closes a circuit from ground, through its right-hand armature and back contact, a contact 336 and the power magnet of sequence switch 301 to grounded battery, for moving this sequence switch into position 10. Upon theY opening of' contact 334 the lamps 415 to 418 are extinguished. In position 10 of the sequence switch 301, a circuit is closed from ground, through sequence switch contact 337, conductor 338, a contact 440, -and the power magnet of indicator switch 403 to grounded battery for moving this switch out of position 7 into its normal position. In the saine manner a ground is connected through the contacts of sequence switch spring 339, conductors 340, 341 and 342 and indicator contacts 441, 442 and 443 to the power magnets of indicator switches 404, 405 and 406, respectively, for moving these switches into their normal position.

In position 10 of sequence switch 301, a circuit is established from ground, through sequence switch contact 343 and the winding of a magnet 344 to grounded battery and under the control of this magnet the brushes 305 to 310 of the trunk finder switch are driven in a downward direction. When they reach their normal position, a contact 345 is closed and a circuit established from ground, through contact 345,'a contact 346 and the power magnet of sequence switch 301v to grounded battery. The sequence switch moves into position 17. IVhen all the indicator sequence switches reach their normal position, a circuit is closed from ground, through contacts 444, 445, 446 and 447, a conductor 448, a contact 347 and the power magnet. of sequence switch 301 to 100 grounded battery for driving this sequence switch into position 18.

While the sequence switch 301 is moving between positions 6 and 17, if an allotter sequence switch 348' reaches position 1, a 105 circuit is closed from ground, through allotter contact 349, sequence switch contact 350 and the power magnet of allotter 348 to grounded battery for moving this allotter into position 4. In this position of the al- 110 lotter, ground is applied through an allotter contact 351 and a contact 352 of a sequence switch associated with another trunk inder switch, for moving that sequence switch out of position 18 into posi- 115 tion 1 and allotting thus that trunk inder for service. As soon as the allotter reaches again position 1, a circuit is closed through contact 349 and sequence switch contact 353 for moving sequence switch 301 out of position 18 into position 1, whereupon the trunk finder will be set in readiness for service.

When sequence switch 205 leaves position 8, the holding circuit of relay 220 is interrupted at contact 223, and this relay releases its armatures.

Cams 231, 232 and 233 are mounted on a constantly rotating shaft 234. These cams are arranged in such a manner that 231 and 232 actuate their respective contact springs .235 and 236 simultaneously-` whereas cam 233 actuates its contact spring 237 prior to the actuation of contacts 235 and 236. When cam 233 actuates spring 237, a circuit is established from ground, through the armature and front contact of relay 226, a sequence switch contact 238, contact 237 and the power-magnet of sequence switch 205 to grounded battery, 4and this sequence switch is moved out of position 9 into position 10. In position l0 of the sequence switch, a circuit is closed from grounded battery, through the left-hand armature `and front contact of relay 214, a conductor 239, the windings of relay 240 and 241, a sequence switch contact 242, the left-hand back contact and'armature of relay 220 and the front contact and armature of relay 226 to ground. Relay 240 becomes energized.l Relay 241 cannot become energized, due to a shunt placed around its winding through the armature and back contact of a ringing cutoff relay '250. Upon the subsequent actuation of contact 235 by cam .231, a circuit is established from a positive superimposed signaling current source 251, contact spring 235, the left-hand winding of ringing cutoff relay 250, sequence switch contact 252, conductor 253, the upper vfront contact and armature of ringing relay 240, the tip contacts of plug 224 and jack 225, limb 254 of the called line, the relays 255 at the stations J, R, M, W, in multiple, limb 256 of the called line, the ring contacts of jack 225 and plug 224, the lower armature and front co-ntact of relay 240, conductor 257, and a se.- quence switch contact 258 to ground.

The relays 255 are responsive to superimposed signaling currents sent out from sources 251 and 259, and by attracting their armatures connect the bells of `all stations into the ringing circuit, but only the bell associated with station W will respondio the current flowing through the circuit. The ringing cut-oil'l relay 250 is marginal, and will not become energized until the called party removes his receiver from the switchhook. When this happens relay 250 becomes energized, current being supplied thereto from sources 251 or 260, depending upon whether contact 235 is actuated or not at this time- Upon the energization of ringing cutoi relay 250, the shunt is removed from around the winding of relay 241, and this relay, by attracting its armature, short-circuits relay 240. A supervisory relay 261 is energized when in the well-known manner, and causes in turn the energization of a supervisory relay 163 at the connecting-operators position.

When the called party desires disconnection he restores his receiver to the switchhook. Supervisory relay 261 becomes deenergized, denergizing in turn supervisory.`

relay 163, and if supervisory relay 164 has also been denergized in response to the hanging up of the receiver at the station 100, the connecting operator removes plug 101 from jack 102. Relay 103 becomes denergized and closes a driving circuit through sequence switch contact 165 for moving sequence switch 105 out of position 16 into position 13. A circuit is now closed through sequence switch contact 166 for energizing a magnet 167 and under the joint control of this magnet and a constantly rotating roller 168, the brush rod 128 of selector 116 is restored to normal. A circuit is then closed from ground, through brush 133, a normal conductin segment 169, conductor 170, a contact 1 1 and the power magnet of quence switch 105 to grounded battery. Scquence switch 105 moves into position l and magnet 167 becomes denergized.

Selector 116 being restored, relay 214 bccomes denergized and opens the circuit of relay 219. A circuit is then closed from ground, through the. back conta-ct and arma-y ture of relay 219, a conductor 245, a contact 246 and the power magnet of sequence switch 205 to grounded battery, for moving this sequence switch out of position 10 into position 1.l When this sequence switch reaches position 1, the lamp 230 is again lighted by way of sequence switch contact 229 and the front Contact and armature of relay 226. The B operator noticing the signal removes plug 224 from jack 225, whereupon the apparatus is restored to normal.

If the called party hangs up his receiver lbefore the calling party has finished the Conversation, the calling party will instruct the connecting operator to rering the called party. The connecting operator actuates key 161 and opens thus the circuit of relay 214. Upon the denergization of this relay, relay 219 is n'laintained energized by a circuit eXtending from ground, through the winding of relay 219, contact 243, conductor 244, the primary of repeating coil 215, sequence switch contact 247, conductor 148, wiper 131, the winding of relay 163 and the secondary of repeating coil 162, to grounded battery. The de'e'nergizationof relay 214 causes the unlocking of relay 241, and when relay 214C again becomes energized upon the releasing of key 161, it will establish in the same manner as above described an actuating circuit for relay 240, and this relay will cause the application of ringing current to the called line in the above described manner.

The bells at the party line stations are arranged in such a manner that the bell of station W responds if the positive current source 251 is connected to the tip side 254 and ground to the ring side 256 of the line. The bell of party M acts ii the negative curl rent source 259 is connected to the tip side 254 and ground to the ring side 256 of the line. The 'bell ot' party R operates it' positive current source 251 is connected to the ring side 256 and ground to the tip side 254 of the line. The bell of party J responds when the negative current source 259 is connected to the ring side 256 and ground to the tip side 254 of the line.

Vhen the operator inserts plug 224 into jack 225 for ringing party 1V, first the sleeve contacts of the plug and jack may Contact, result-ing in the energization of relay 226, whereupon, as above described, sequence switch 205 moves into position 9. While the plug is being pushed into the jack, the tip of lug 224 may contact with the ring of the j ac Should the ringing current source 251 already be connected through contact 252, positive pulsa-ting current would be applied to the ring conductor 256 and thus a station like R, where the bell is normally connected to the ring side of the line, would be signaled. However, as above described, contact 252 is closed only after cam 233 has operated spring 237, that is to say, while both ringing current sources 251 and 259 are disconnected at contact springs 235 and 236 of cams 231 and 232. Due to this arrangement the touching of the ring contact of jack 225 by the tip of plug 224 will not result in the ringing of a station, this being performed only after the plug has been positively inserted into the jack. v

If the signaling of party R is desired, the connecting operators controlling apparatus controls the moving of indicator 406 into position R, in which position contacts 425 and 426 are closed. When, therefore, sequence switch 205 reaches position 8, a circuit is established from grounded battery through contact 426, conductor 427, sequence switch contacts 260 and 222, and the righthand front contact. armature and winding of relay 220 to ground. The rela-y 220 will thus notbe denergized when contact 221 is opened, but remains held up through this circuit until the sequence switch reaches position 11, whereupon a new circuit is closed for relay 220 from grounded battery through contact 425, conductor 428, sequence switch contacts 261 and 222 and the right-hand contact, armature and winding of relay 220 to ground, for maintaining this relay energized. Relay 220 keeps thus the driving circuit of sequence switch 205 closed at its left-hand armature through sequence switch contact 228 until the sequence switch reaches position 14, whereupon the holding circuit of relay 220 is opened at Contact 261 and the sequence switch 205 is moved under the control of its normal spring into position 15. The circuit of relay 210 being held open at the left-hand back Contact of relay 220, this relay 240 cannot become energized until sequence switch 205 leaves position 14. When cam 231 actuates Contact spring 235, a circuit is closed from the positive current source 251 through the left-hand Winding of ringing cut-off relay 250, sequence switch contact 262, the lower contact and armature of relay 240, conductor 257, the ring contacts of plug 224 and jack 225, line conductor 256, relays 255 in multiple, line conductor 254, the tip contacts of jack 225 and plug 224, the upper armature and front contact of relay 240, conductor 253 and sequence switch contact 263, to ground. The bell of station R responds to this current as previously described.

If the signaling of party M is desired, only contact 426 is closed and therefore relay 220 becomes denergized when sequence switch 205 reaches position 11, its circuit being open at contact 260. The sequence switch 205 stops in position 12, from which position it is moved out under the control of cam 233 in the same manner as was described in connection with the signaling of party W. The ringing circuit for party M is established through sequence switch contacts 264 and 258, the ringing relay 240 being energized when sequence switch 205 leaves position 11.

If party J or a direct line is desired, then contacts 426, 425 and 430 are closed. When sequence switch 205 reaches position 14, a circuit is established from grounded battery through contact 430, conductor 431, sequence switch contacts 265 and 222, and the righthand front contact, armature and winding of relay 220 to ground. This relay holds its armature attracted in position 15 of sequence switch 205, and the sequence switch is moved into position 17. In position 16 of the sequence switch, relay 220 lbecomes deenergiz'ed and closes the circuit of relay 240, whereupon the ringing circuitis established through sequence switch contacts 266 and 263.

It will be seen from the above that the circuit of ringing relay 240 adapted to associate the selected ringing current source with the line is maintained open at the4 left-hand back contact of relay 220 until sequence switch205 reaches positions 8, 11, 14 and 16, respectively, depending upon the setting of indicator 406. If, for example, the signaling of party R is desired, the ringing relay cannot become energized until after sequence switch 205 has left position 14, and therefore the ringing of stations W and M, while this sequence switch is moving through its operating positions 10 and 13, is positively prevented.

Although only one trunk 147, 148 extending between the district selector and plug 224 has been shown in Fig. 2 of the drawings, it will be obvious to those skilled inthe art that in commercial telephone systems there are a plurality of such trunks,

cach trunk being provided with controlling apparatus (relays, sequence switches etc.) similar to those shown in Fig. 2.

What is claimed is:

l. In combination, a variably adjustable sender the impulses of which are all of like character, a relay, a circuit for operatively associating said sender with said relay, a plurality of selectively operable switching devices, a -controlling circult extending from said relay toward said devices, and a single relay for controlling the successive association of said devices with said controlling circuit.

2. In combination, a variably adjustable sender, a plurality of switching devices operable in accordance with the adjustment of said sender, a relay, an energizin circuit for said relay controlled by sai sender, means operable when said relay is energized for operatively associating one of said devices with said sender, and means operable upon the initial de'e'nergization of said relay for operatively associating another one of said devices with said sender.

3. In combination, a variably. adjustable senden'a plurality of switching devices operable in accordance with the adjustment of said sender, a relay, means controlled by said sender for energizing and denergizing said relay and means o erable in response to each operation 'of said-relay for successively associating said devices with said sender.

4. In combination, a variably adjustable sender, a plurality of switchin devices operable in accordance with the a justment of said sender, a relay, an energizing circuit i for said relay controlled by said switchingv devices, means operable when said relay is energized for operatively associating one of said devices with said sender, and means operable when said relay is denergized for operatively associatin another one of said devices wlth said sen er.

5. In combination, a variably adjustable sender, a plurality of switching devices operable in accordance with the adjustment of said sender, a relay, an energizing circuit for said relay jointly controlled by said devices and said sender, means operable when said relay is energized for operatively associating one of said devices with said sender, and means operable when said relay is'deenergized for operatively associating another ,one of said devices with said sender.

6. In combination, a sender, a plurality of switching devices opcrable in accordance with the adjustment of said sender, a relay for controlling the successive association of said devices with said sender, an energizing circuit for said relay controlled by said sender, and a holdin circuit for said relay controlled by one o said devices.

7. In combination, a variably adjustable sender, a plurality of switching devices operable in accordance with the adjustment of said sender, a relay for controlling the successive association of said devices with 4said sender, van energizing circuit for said relay jointly controlled by said sender and said devices, and a holding circuit for said relay controlled by said devices.

8. In combination, a variably adjustable sender, a plurality of switching devices variably operable in accordance with the adjustment of said sender, a controlling cirvariably adjustable cuit extending from said sender toward said devices, a relay operable under the joint control of said sender and said devices, an operating circuit having two branches for each of said devices, a back contact for said relay for operatively connecting one branch of any one of said operating circuits to said controlling circuit, and a front contact for said relay for operatively connecting the other branch of any one of said operating circuits to said controlling circuit.

In witness whereof I hereunto subscribe my name this l11th da of April, A. D. 191".

ALB N E. LUNDELL. 

